It is already known that the function of a boundary-mark consists in temporarily closing a space to vehicles while letting pedestrians cross when it is in its raised position or when it is protruding above the ground, and to enable authorized people to put their car in the space in question once the boundary-mark has been retracted into the ground by hand for example. Various systems for locking this kind of boundary-mark in a raised and/or a lowered position are already known, but they are not satisfactory particularly because they are not reliable enough, they are fragile and can be forced by hooligans, while another disadvantage arises from the fact that users may fail to put the boundary-mark back in its raised position once they have got over it.
The present invention therefore aims at providing a locking device of the above-mentioned type which overcomes the disadvantages of known systems and which is solid and reliable while being relatively inexpensive.
Another purpose of the invention is to provide a device which prevents the users from leaving the boundary-mark in its retracted position, that is in its lowered position once their car has gone over the device.
A further object is to protect such device from the harmful effect of outside agents such as surface waters, dust, sand and gravel.